In communication in business activities, phones are used commonly not only indoors, such as inside company buildings, but also outdoors. As a technique related to such a phone use environment, for example, Patent Literature 1 discloses a private branch phone system that includes a fixed-line phone terminal and a mobile phone terminal.
This private branch phone system includes a connection switching unit that switches whether an incoming call to a phone number assigned to the fixed-line phone is to be connected to the fixed-line phone or to a mobile phone terminal via the fixed-line phone. Thus, the private branch phone system can switch whether the fixed-line phone or the mobile phone terminal is to be used.